DNA structure diagram labeled
Nucleic acids are vital organic molecules present in all living organisms in the form of DNA or RNA. These molecules are built from nitrogenous bases, sugar molecules, and phosphate groups, all connected in a specific sequence. Among them, DNA (Deoxyribonucleic Acid) is the molecule that carries hereditary information, defining the genetic makeup of almost every organism on Earth. Structurally, DNA forms a double helix — a twisted ladder made of nucleotides, where each nucleotide contains a sugar, phosphate, and one of four nitrogen bases: adenine, thymine, cytosine, and guanine. These bases pair specifically (A with T, C with G), maintaining the stability and precision of genetic information.
DNA not only determines inherited traits but also plays a fundamental role in protein synthesis and cellular function. It exists mainly as nuclear DNA within the cell nucleus, while smaller portions like mitochondrial DNA and plastid DNA perform essential tasks such as energy production and photosynthesis. The DNA molecule coils to form chromosomes, with humans carrying 23 pairs inside each cell nucleus. This extraordinary molecule truly serves as the blueprint of life, transmitting genetic instructions from one generation to the next.
